Jessica Scorpio was a grad student at Singularity University--a sort of futurist boot camp on the old NASA Ames base near Mountain View, Calif.,--and the challenge was this: build a company that would have a positive effect on a billion people during the next 10 years.

She and the nine other members of her team decided to focus on energy and the environment. "Since the transportation industry hasn't really changed much in the past 50 years," says Scorpio, 23, "we thought it was pretty ripe for some innovation."

During research, the group noticed that the basic model of car ownership created a lot of waste. Just think about it: Most cars sit idle for the majority of their existence. So the group brainstormed and came up with the idea of person-to-person car sharing. Scorpio and her team worked feverishly for a month to develop a prototype. From that came their biggest feat: Creating a small geo-locating hardware device that sits in a vehicle and communicates with smartphones to control access.

Greening 101

Jessica Scorpio's advice for building an environmentally aware company:

4. Select team members who live and breathe for the business. ("One of our top advisors initially told us that he would not join our team unless he knew that everyone would work on it full time.")

They named their company Getaround, and here's how it works: Car owners install the $100 device, then register on the network and set their own rental prices and schedule. They decide who rents and who doesn't, partly based on feedback ratings similar to eBay's. Meanwhile, renters simply hop on getaround.com or use a Getaround iPhone app to search for available cars nearby. If the owner approves a rental request, the app will unlock the car and grant access to the keys.

The hope is Getaround will reduce how much people drive (car sharing cuts driving by 40 percent to 44 percent, Scorpio says). And that, in the end, will reduce greenhouse gas emissions.

Getaround has some angel investors, including founders of Singularity University. And the company is pursuing millions in grant money earmarked for sustainability programs from the U.S. Department of Transportation.

"Other car rental companies have huge overhead expenses related to purchasing vehicles and have issues related to fixed locations," Scorpio says. "But we can very quickly have inventory on every street corner without having to shell out a fortune."

Getaround is being tested in Mountain View and at the University of California, San Diego, and is planning programs with other UC campuses and California cities. If all goes well, Scorpio and company plan to expand nationwide.